ElasticSearch client-only config param is incorrect

[dhm116]

In the rexster template (line 105) the correct configuration is:

<storage.index.search.elasticsearch.client-only>true</storage.index.search.elasticsearch.client-only>

This corrects the following exception I noticed in the container logs:

6107 [main] INFO  com.thinkaurelius.titan.diskstorage.configuration.BasicConfiguration  - Ignored configuration entry for storage.index.search.backend since it does not map to an option
java.lang.IllegalArgumentException: Unknown configuration element in namespace [root.storage]: index
    at com.google.common.base.Preconditions.checkArgument(Preconditions.java:120)
    at com.thinkaurelius.titan.diskstorage.configuration.ConfigElement.parse(ConfigElement.java:168)
    at com.thinkaurelius.titan.diskstorage.configuration.BasicConfiguration.getAll(BasicConfiguration.java:83)
    at com.thinkaurelius.titan.graphdb.configuration.GraphDatabaseConfiguration.<init>(GraphDatabaseConfiguration.java:1224)
    at com.thinkaurelius.titan.core.TitanFactory.open(TitanFactory.java:92)
    at com.thinkaurelius.titan.core.TitanFactory.open(TitanFactory.java:71)
    at com.thinkaurelius.titan.tinkerpop.rexster.TitanGraphConfiguration.configureGraphInstance(TitanGraphConfiguration.java:33)
    at com.tinkerpop.rexster.config.GraphConfigurationContainer.getGraphFromConfiguration(GraphConfigurationContainer.java:124)
    at com.tinkerpop.rexster.config.GraphConfigurationContainer.<init>(GraphConfigurationContainer.java:54)
    at com.tinkerpop.rexster.server.XmlRexsterApplication.reconfigure(XmlRexsterApplication.java:99)
    at com.tinkerpop.rexster.server.XmlRexsterApplication.<init>(XmlRexsterApplication.java:47)
    at com.tinkerpop.rexster.Application.<init>(Application.java:97)
    at com.tinkerpop.rexster.Application.main(Application.java:189)